/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/SubRegionRemesher.h
Tell a MeshChangeTracker about the set of triangles that we might modify in the next remesh pass. This could include one-rings of either side of an edge in the ROI, if we collapse.
void SaveActiveROI ( [FDynamicMeshChangeTracker](API\Runtime\GeometryCore\DynamicMesh\FDynamicMeshChangeTracker) * Change )